Reversible internal-combustion engine.



. e. c. DAVISON.

JBEVE RSIBLE INTERNAL COMBUSTION ENGINE.

. APPLICATION FILED MAY 5. I915.

Patented June 19, 1917.

INVIEIVTOR 5. Q BY ISHEETS-SHEET 1. 4

A TTORNEYS G. C. DAVISON.

REVERSIBLE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED MAY 5. l9l5.

Patented June 19; 1917.

2 SHEETS-SHEET 2.

m 2 Q 6 M v II l I I 0 f iII o m l I m Z 2 I K 7 4 2 m ATTORNEYS insoles.

GREG-CRY o. navrson, or new LONDDN, c

co rANY, or new YORK, n. r,

ONNECTICUT, ASSIGNOE "E0 ELECTRIC BOAT A CORPORATION GF NEW JERSEY.

,REVERSIIBLE INTERNAL-CQMBUSTION ENGINE.

To (ZZZ whom it may concern:

. Be it known that I, GREGORY G. DAYISOX,

citizenfoir' the United States,'residing at.

New London, in the county of New London and State of Connecticut, have invented cer-' l his invention relates to internal com-' bustion engines and more particularly, to the'construction of such engines whereby they may be reversed and operated in either direction. The invention may be employed in internal combustion engines of various types but is of special utility in internal combustion engines employing liquid oil as the fuel and operating on the Diesel cycle.

' In orderto provide for the reversing of an internal combustion engine, it has been common heretofore to provide two cams for opcrating each of the several valves; with this construction the operation of reversing involves raising the valve-litters tree of the cam-shaft, then sliding the cam-shaft axially so that one set of camsis rendered inoperative and the other operative and then lowering the valve-litters into c'oaetion with the cam-shaft. This construction involves the XlSG Of numerous parts whose operation is not as smooth and reliable as is desired. lhe present invention is directed to the provision oztan. improved construction whereby an internal (:OlllbUStlOIl' en ine is adapted for reversal, thisconstruction involving the use of a less number of parts which will operate in a smooth and reliable manner.

It has been proposed heretofore to provide means for turning the cam-shaft of an internal combustion engine angularly in its bearings relatively to the crank-shaft of the engine so as to carry the cams on the camshaft fronr-the positions for operating the engine in one direction to for operating the engine in the opposite direction. This expedient, however, is unsatisfactory for the reason that all of the valves shifted angularly the same amount. I have found that provision 1r he J'iadeii'or the reversal o1 an internal mi ustion engii'ie simpleand otter se ;a\rate cant-s t ie, p ositions" Specification M Letter's Patent. rm n Jung 19, 1917, Application filed ma 5, 191.5. Serial No 25,903.

' of the engine in the reverse direction. The

several mechanisms for shifting the camshafts may be operated simultaneously by a single operating device, but by reason of the employment of a plurality of cam-shafts,

one for each cam or set of "ams. which shafts may be shifted predetermined but difierent amounts, the cams may be established in the relation to the engine shaft which is found to be mostconducive to proper operation in the reversedirection. In a multi-cylinder engine, theseveral cam-shafts may extend along the whole series of cylinders and each shaft may carry all of the cams of one set, that is, all of the cams for operating the inletvalves of all of the cylinders or all of the cams for operating the exhaust valves of all ofthe cylinders; in no case, however, are cams of two ditl'erent sets, as for instance,

.acam for operating an exhaust alve and a cam for operating an inlet valve, mounted upon the same cam-shaft.

I have illustrated one form in which the invention may be embodied in the accompanying drawings which show an engine of the Diesel type, but it will be understood that the invention may be employed in other forms of internal combustion engines whether operating on the Diesel cycle or not and in engines having valve gears differing materially in construction from that illust-rated.

In the drawings, Figure 1 is an ent of an internal combustion engine; Fi an elevation of a portion of the engine, 4 5. 3 and 4: are detailed views of the operating device for shifting the cam-shafts angularly and 5, 6, T and 8 are diagrammatic viewsillustrating the actioncf the cams and the parts operated thereby.

Referring to these drawings, an internal combustion engine is shown having a casing 1 wliich is"mounted for rotation in bearings formed on the casing 9. Each cylinder 10 i an exhaust valve 12 and in the present i": Lance this exhaust valve is shown as operconnected'to cranks on the crank-shaft 11- .9 upon which are mounted aplurality of p ared by a pivoted lever 13 one end of which" carries a member which is adapted to engage and operate the exhaust valve 12; the other end of this lever 13 carries a roller which bears on the periphery of a cam 11 carried by a cam-shaft 15 mounted for rotation in suitable bearings secured to the casing 9. Each cylinder is also provided with an inlet valve 16 which is here shown as operated by a pivoted lever 17, one end of which carries a member. which is adapted to engage and operate the inlet valve 16; the other end of this lever 17 carries a roller which runs upon the periphery of.a cam 18 secured to a cam-shaft 19 which is mounted for rotation in bearings on the casing 9. The engine illustrated being. of the Diesel type, a spray valve is shown at 20; this valve is operated by a bell-crank lever 21 pivoted in a bracket secured to the cylinder ,10 and the bell-crank 21 is operated by a pivoted lever 22, one end of which carries a member which is adapted to engage and operate the bell crank -21;

which travels on the periphery of a cam 23 secured to a cam-shaft 21 mounted for rotation in bearings directly above the camshaft 19.

As many cylinders 10 may be provided as is desired, the additional cylinders being arranged at the left of the one shown in Fig. 2 with all of the cylinders in line, and with the cam-shafts 15, 19 and 21 extending along all of the cylinders. Each of the cam-shafts 15, 19 and 21 carries all of the cams of one set,

that is, the shaft 15 carries the cams for. op-

crating the exhaust valves of all of the cylinders, the shaft 19 carries the cams for operating the inlet valves of all of the cylinders, and the shaft 21 carries. the cams for operating the spray valves of all of the cylinders. In no case are cams of two different sets, as for instance, a cam for operating an exhaust valve and a cam for operating an inlet valve, mounted upon the same cam-shaft.

In order toeffect the reversal of the direction of operatlon of the engine, the camshafts 15, 19 and .21 are turned angularly in their bearings relatively to the crank-shaft 11 so as to carry the cams on the cam-shafts to new positions in which they will operate in the manner appropriate to'the running of the engine in the reverse direction. 'But the mechanism for effecting this angular shift of the cam-shafts includes individual connections to each of the several cam-shafts so that those shafts may be turned different angular amounts. Preferably, 'a single operating device is employed for effecting the angular shiftof all of the cam-shafts. but the construction is such that the direction and n'iagnitude of the movement of one camshaft is in'ho way dependent upon the direction and magnitudeof the movement of an other cam-shaft.

The several cam-shafts are driven from the crank-shaft in any suitable manner. In

these several gears are such that the shafts 15 and 19 are driven at one-half of the speed of the crank-shaft 11 and the shaft2'1 rotates in unison with the shaft 19. Between the cams on the shafts 21, 19 and 15, and the gears by which those shafts are driven, each of the shafts is divided as shown in Fig. 1

and on each shaft is an axially movable sleeve for effecting the connection between the two parts of the shaft. Each sleeve 3() has at one end thereof a spline connection 31 to one part 32 of the divided shaft. At

the other end of the'sleeve .a plurality of blocks or shoes 3,3'are secured to the sleeve within the opening therein and in positions to enter spirally arranged grooves provided for their receptionin the end of the can shaftproper, as shown at 31 in Fig. 1. A sleeve connection of this construction is employed in connection with each of the three cam-shafts 15, 19 and 21, but the pitch of the spiral grooves 31 in the three cam-shafts is not the same, lhe three sleeves 30 may be moved axially simultaneously by a single operating 7 device and when they are so moved, they turn the cam-shafts relatively to the crank-shaft by amounts determined by the pitch of the several threads 31. Each of the sleeves 30 has a circumferential groove formed therein to accommodate a ring as shown in Fig. 1 which ring receives the ends of screws 35 carried by a yoke'36. This yoke may be moved back and forth in any suitable manner, that is, manually, pneumatically or in any other desired manner. Inthe present instance, a pivoted operating lever is shown at 37 pivoted upon the casing of the engine and connected to the yoke 36 so asto operate the same. It will be seen that by moving the operating device 37 from one limlt ofits. range of movement to the other, the three cam-shafts and all of the cams thereon will be shifted angular-1y independently of they crank-shaft and that the extent and direc-i tion of movement of the cams of one set will not be affected by or dependent on the extent or direction of' movement of the camsof another set, but on the contrary will depend wholly upon the pitch ofthe grooves 31 provided in the cam-shaft. In the case of a Dieselengine of theconstruction. shown in Figs. 1 and such that movement of the operating device 2, the sp rally arranged grooves in the ends of the cam-shafts may be '37 from one limit of its range of movement to the other Willcause the exhaust cam-shaft 15 to be turned backward approximately 90, the inlet cam-shaft 19 to be turned forward approximately -90", and the cam-shaft 24 for the spray valves to be turned ahead somewhat less than 90.

propriate for running ahead to positions ap. prouriate for running astern.

The diagrams in Figs. 5 to 8 illustrate the movements of the cams throughout one cycle of operations when running ahead and when running astern. The raised portions of the several cams are shown in full lines 'on Fig. 5 and the direction of rotation of the crank-shaft when the engine isrunning astern is indicated by the arrow on Fig. 8. Also/the arrows applied to the cams on Fig. 5 indicate the direction of rotation'of the cam-shaftswhen. running ahead and the arrows applied'to the cams on Fig 8 indicate the direction of rotation of the camshafts when running astern. Following the operation of the engine when running ahead, Fig. 5 shows the piston at the beginning ot' the downward stroke when air is admitted to the cylinder in .order to fill the cylinder with pure air. It will be seen that the raised portion of the inlet cam 18 is about to open the inlet valve 16 and that the exhaust valve 12 and spray valve 20 are closed. The piston moves downward to the position shown in Fig. 6 and during this half rotation of the engine shaft, the cam- Sdflft is turned through onequarter of a revolution at the end of which the raised portion of the inlet cam 18 passes beyond the coacting lever 17 so that the inlet valve 16 closes. The piston then moves upwardly in the cylinder com-pressing the air'therein. all of the valves remaining closed. At the end of the upward movement of the pis- -ton the raised portion of the spray cam 23 operates to open the spray valve 20, as shown in Fig. 7; s9 that the charge of fuel is admitted to the cylinder. The spray valve closes immediately and the charge of fuel. becoming ignited, expands and drives the piston downwardly to the position shown in Fig. 8. Then as the piston starts upwardly again the exhaust cam ll opens the exhaust valve 12, as shown in Fig. 8. so. that during the upstroke of the pistointhe products of combustion are expelled through the exhaust valve.

In order to reverse the direction of operation of the engine, the operating lever 37 is I p This extent and di- 'rect-ion of movement of the cam-shafts will .i carry all of the cams from the positions apmoved as above described and the cams are shifted from. the full line positions to the dotted line positions; the exhaust cam 14: is turned backward approximately 90, the inlet cam 18 is turned ahead approximately 90, and the spray cam 23 is turned ahead somewhat less than 90, thewords backward and ahead being here used with reference to thearrows on Fig. 5 indicating .the direction of rotation of the cam-shafts when the engine is running ahead. 'Follow ing the operation when running astern, Fig. 8 shows the parts in the positions they occupyat the beginning of the compression stroke. The raised portion of the inlet cam has just passed by the roller on the end of the lever 17 sothat the inlet valve 16 has closed after admitting pure air to the cylinder. The piston moves up, compressing the air in the cylinder and at the end of the upstroke, the parts being then in the position shown 111 Fig. 7, the spray valve is opened 'momentarily so as.to admit fuel to the cylinder. This fuel is ignited and by-its expansion moves the piston down to the position shown in Fig. (3. As the piston starts on its upward movement, the exhaust cam opens the exhaust valve so that the products of combustion may flow out of the cylinder' during the upward movement of the piston which carries the parts to the positions shown in Fig. 5. lVhen these positions are reached, the inlet valve 16 is opened by its cam 18 so that pure air is admitted to the cylinder while the piston is moving down to the Fi 8 position.

In engines of the character illustrated, it is usual to provide means whereby the engine may be started by compressed air. Provision may be made for starting in this manner in combination with the construction illustrated in the drawings, but as any suitable form of compressed air starting mechanism may be employed. illustration and description thereof in connection with the present invention is believed to he unnecessary.

What I claim is:

1. A reversible internal combustion engine of the Diesel ty-pe comprising the combination of a cylinder, a piston reciprocating therein, a crank-shaft to which the piston is connected, inlet, exhaust and spray valves for the cylinder, three cams for operating said valves. means for causing the gine comprising the combination of a cylinder. a piston reciprocating therein. a crank shaft to which the piston is connected, three substantially 1 valves for the cylinder, three cams each adapted to actuate one of thevalves, means for causing the crank shaft to rotate said cams, and a single means for shifting the three cams angularly predetermined amounts, one of them an amount different from the others, to position the cams for operation of the engine in the reverse direction; substantially as described.

3. A reversible internal combustion ,engine of the Diesel type, comprising the combination -of a cylinder, a piston reciprocating therein, a crank shaft to which the piston is connected, inlet, exhaust and spray valves for the cylinder, three cams each operating one of said'valves, three shafts each carrying one of the cams,'means for causing the crankshaft to rotate all of the camshafts, and a single means for shifting all three of. the camshafts angularly predetermined amounts relatively to the crank shaft to position the cams for operation of the engine in the reverse direction; substantially as described.

4. A reversible internal combustion engine of the Diesel type comprising the combination of a cylinder, a piston reciprocating therein, a crank shaft to which the pistion is connected, inlet, exhaust and spray valves for the cylinder, three cams for operating said valves, means for causing the crank shaft to rotate said cams, and means for shiftingthe three cams angularly relatively to the crank shaft predetermined amounts, one of them an amount different from the others, to position the cams for operation of the engine in the reverse direction; substantially as described.

7 In testimony whereof I affix my signature, in presence of two witnesses.

. GREGORY C. DAVISON:

"Witnesses'z F. L. BRAKE, J. W. ANDERSON. 

